The automotive industry has over the years continually exerted efforts to improve both the fuel economy and the operating performance of automotive engines.
The trend has been, and continues to be, to employ various forms of fuel injection apparatus in order to be able to meter the rate of fuel flow to the associated engine with an accuracy greater than that attainable as by, for example, carburetor structures.
Prior art fuel injection systems may be grouped, broadly, into two categories. That is, a first of such categories would comprise those systems wherein the fuel injector (or injectors) inject metered fuel into the induction passage means of a throttle body structure from where the resulting fuel-air mixture flows to be divided among a plurality of branches or runners of a downstream-situated induction or intake manifold and ultimately delivered to and discharged in close proximity to the respective intake valve means of the plurality of engine cylinders. This first category at times experiences difficulties in that because of design, packaging and/or manufacturing tolerances employed in the production of intake manifolds, for example, the flow characteristics of all of the branches or runners of the intake manifold are not identical. This, in turn, results in certain of the engine cylinders experiencing fuel "starvation" and, generally, the manner of correcting such fuel "starvation" is to increase the total rate of metered fuel to the engine so that no engine cylinder experiences any fuel "starvation". However, by employing such a corrective approach other engine cylinders, of necessity, are provided with an overly rich (in terms of fuel) fuel-air mixture which, of course, means that the potential maximum fuel economy of the engine is not being attained.
The second category would comprise those systems wherein respective ones of a plurality of fuel injector assemblies are situated so as to discharge metered fuel in close proximity to respective intake valve means of the corresponding engine cylinders thereby providing greater assurance that each engine cylinder will be supplied with the required rate of metered fuel flow especially since such metered fuel does not have to flow through the effective length of the intake manifold runners and thereby possibly be deleteriously affected thereby.
However, both of such categories continue to experience the problem of obtaining a desired or optimum degree of metered fuel atomization. Generally, the greater the atomization of fuel, the better the combustion process will be within the engine cylinder which, in turn, will provide always desired better engine performance, reduced engine exhaust emissions and increased engine fuel economy.
Accordingly, the invention as herein disclosed and described is directed primarily to improving the atomization of injected fuel as well as to the solution of other related and